School under the Invisible Dome

On Daisy Street, right next to the old park, stood a school that everyone thought was completely ordinary. But for Lena, Olek and Iga, this school had one secret: every week, at exactly midnight from Thursday to Friday, a glass-transparent dome appeared around the building that only they could see. One cold night, armed with torches and a lot of courage, they decided to check it out. As they crossed the invisible boundary, suddenly Lena felt something strange tingle in her hands. Olek's ears buzzed and Iga noticed that her shadow on the wall was moving on its own. Before they had time to exchange puzzled glances, the torchlight began to swirl to form a luminous vortex, and colourful flashes appeared all around. - Do you see it! - cried Olek. His voice echoed as if he was inside a huge shell. Trying to look around, Lena raised her hand and... suddenly her fingers became transparent and began to disappear. The girl moved away from her friends in horror, but they were even more surprised. Iga, looking at her shadow, noticed that it was taking the shape of a big cat, which was wagging its tail cheerfully at her. - If this is a dream, it's a very strange one... - whispered Iga and tried to touch her shadow. At the same moment, Olek felt his footsteps make no sound, and when he jumped up, he was lifted into the air like a hot air balloon. Suddenly, a mysterious green light flashed from inside the school, from behind the large windows of the old gymnasium. Strange whispers could be heard, and the door to the school slowly began to open with a protracted creak....